Cable dispensing system

ABSTRACT

A cable dispensing system is disclosed which includes multiple parallel coils of flexible non-insulated cables separated by multiple parallel insulating discs. The insulating discs have hubs to which the inner portions of the coils are fixedly coupled. The insulating discs and coils are disposed within a housing, which is rotatably coupled to the multiple parallel insulating discs and fixedly coupled to each outer portion of the multiple coils. The cables comprising the coils are routed from the inner portions through tunnels, which extend through the insulating discs in paths parallel to the axis of the parallel insulating discs. When cords attached to the housing are extended, the coils become wound, creating an electrical short between adjacent loops of the spiral coil. The shorter conductive path reduces the amount of energy that is lost as heat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of International Application No. PCT/IB2010/002453, designating the United States, with an international filing date of Sep. 13, 2010, which claims the priority benefit of U.S. application Ser. No. 12/558,430, filed Sep. 11, 2009, now U.S. Pat. No. 8,118,147.

TECHNICAL FIELD

The disclosed embodiments relate generally to cable dispensing systems. In particular, the disclosed embodiments relate to an electric cable dispensing system used for recharging the batteries of electric vehicles.

BACKGROUND

Electric vehicles are becoming more popular. Unfortunately, current battery technology requires batteries for electric vehicles to be recharged frequently. Accordingly, there is a need for systems that can quickly and efficiently couple an electric vehicle to a charge station to recharge the batteries of such vehicles.

The 120V-240V electrical outlets commonly available worldwide have several drawbacks for recharging car batteries. First, charging takes a substantial amount of time because of relatively low voltage sources. Second, the high current required for charging the batteries often results in inefficiencies, including loss of energy as heat. Therefore, there exists a need for a retractable cable dispensing system that reduces energy loss and recharges car batteries more quickly and conveniently.

SUMMARY

The present invention addresses the above deficiencies and other problems associated with prior retractable cable dispensing systems. Embodiments of the present invention may operate at medium and/or high voltage, which reduces the current and associated energy loss. The invention utilizes continuous conductive elements to provide electrical connections between two parts (e.g. a stator and a housing) which are displaceable with respect to one another (as a result of movement/rotation of one of them or both). The invention may therefore be utilized in medium and high voltage applications for which continuous and stable electrical connection(s) are required (for example for safe and reliable connection of a protective earth/ground conductor). For example, instead of traditional non-continuous electricity conducting mechanisms such as slip-rings and touch brushes, which are typically used for conducting electricity between relatively movable/rotatable parts, embodiments of the present invention use continuous conductive element(s), such as spirals, to provide electric conductivity between electric terminals/contacts coupled to the respective moving parts thus allowing the relative movement between those moving parts while providing and maintaining continuous and stable electric contact.

It should be noted here that the terms low-, medium- and high-voltage are considered herein in accordance with the general/standard definitions according to which: “High voltage” refers to alternating-current (AC) voltage over 1000 V or direct-current (DC) voltage over 1500 V; “Medium voltage” refers to voltages in the range of 50-1000 V AC or 120-1500 V DC over 1000 V or direct-current (DC) voltages over 1500 V; and “Low voltage” refers to voltages below 50 V AC or below 120 V DC.

In addition, the present invention allows efficient electrical conduction through the retractable cable dispensing system having reduced resistance and thereby reduced energy loss. As is generally known, the electrical resistance of a conductor is linearly proportional to the length of the electrical path through the conductor. Thus, in some embodiments of the invention the bindings of the coils/spirals, which provide continuous electrical connection between the two moving elements, are configured to be tightened to one another when the cable is retracted, thus creating an electrical short between the bindings/loops of the coils. This provides that the electrical path through the coils/spirals is decreased as the coils are tightened during use e.g. when the cable dispensing system is extracted and an electric cable is dispensed thereby. To this end it should be understood, that the number of bindings in each spiral and the nominal radii of the bindings are selected such that an electrical contact would be formed between at least some of the bindings in the radial direction at least when the cable is extracted over a certain length. In some cases, also the crossectional shape of the spiral conductor is selected to improve the electrical coupling between adjacent bindings when the latter are close to one another. For example flat or flat-braid cables may be used for this purpose. This is explained in more detail below.

Yet additionally, in some embodiments of the invention, it provides a modular design for such a cable dispensing system allowing extraction and retraction of a cable that may include any number of electrical wires, as well as communication/data transmission cords/lines, where all the electrical wires and possibly also the communication/data transmission cords are accommodated in a single cable (e.g. within a single insulating cable cover). This is achieved according to the invention by utilizing a housing of the cable dispensing system, on the outside circumference of which the cable that is to be retracted/contracted is wrapped. The housing may for example have a cylindrical shape. The housing at least partially encloses a stator module defining a rotation axis of the housing relative to the stator. Typically, the stator may be associated with an anchor or may be fixedly mounted, for example to a charging pole, wherein the housing is configured to be rotatable relative to the stator for retracting or releasing the cable wrapped thereon. When connected to a charging pole/post, one or more continuous electrical connections and possibly also continuous data transmission cords are provided between the cable wrapped/connected to the housing and the electrical connections/terminals of the stator by which the cable dispensing system is connected to the charging pole. The one or more continuous electrical connections are provided by one or more coils/spiral conductors whose inner end is fixedly attached to the stator and outer end is fixedly attached to the housing and electrically connected to the wires/data-cords of the cable wrapped thereon. The one or more spiral conductors are typically arranged within the housing with a spaced apart, coaxial and collinear arrangement about the stator. This provides a modular design by which any number of such conductive spirals may be accommodated side by side coaxially about the stator. Accordingly, any desired number of continuous electrical connections and data transmission cords may be provided between the housing and the stator while also enabling the same number of connections to be connected to a single cable wrapped about the housing. Specifically, the cable dispensing system of the invention may be used to provide a single-phase or a three-phase electrical connection (i.e. including 3 and 5 electric wires respectively) and may also provide therewith a data communication connection.

Providing a modular design of the cable dispensing system, which may be configured to carry any number of conductor/wires and data lines, has also commercial advantages as the same elements/modules may be modularly assembled to provide different types of retractable cable dispensing systems. Specifically, in vehicle charging applications, single phase and three phase chargers may coexist together for charging vehicles and may accordingly require retractable cables which may support both three- and five-wires electrical connections plus data connections. Providing a modular design satisfying both requirements allows efficient and less costly production of such modules.

It should be understood that the modular design provided by the invention also allows some of the electrical connections between the housing and the stator to be non-continuous connections such as those achieved by the slip-rings and touch brushes mechanisms. Specifically, in some cases it might be essential to provide continuous grounding (earthing) connection while for other electrical connections such as the phase and neutral electric wires, non continuous electrical connections may be used. For example, for some electrical connections, the typical known in the art slip-rings and touch brushes mechanism may be used in between the stator and the housing, while for one or more other connections, such as ground connection, the continuous spiral conductor connection may be used. In such a combination the slip-rings and touch brushes mechanism(s) and the spiral conductor may be arranged side by side, and coaxially and collinearly with respect to the stator to provide multiple electrical connections between the stator and the housing/cable. In this regard, it should be noted that the signal/data transmission between the housing and the stator may be provided by a spiral data cord which may include multiple signal lines and/or by slip-rings and touch brushes mechanism.

An additional advantage of the present invention is associated with the small footprint/form-factor of the retractable cable dispensing system. The small form-factor is achieved by utilizing non-insulated conductive spirals for conducting electric power between the housing and the stator. In general, the electric insulation of an electric wire is associated with a substantial part of the wire's volume, thus by obviating use of insulated conductors/wires in the spirals, the size of the housing may be reduced. In particular, obviating use of an insulation in the spirals provides significant reduction in the sizes of dispensing systems for medium voltage, high power applications, such as charging, for which the thickness of the insulation layer is significant.

Specifically, according to some embodiments of the invention, the coils (or some of them) are configured such that as the cable is extracted and the housing is rotated with respect to the stator for releasing the cable wrapped thereon (reducing the number of windings of the cable), then the number of windings of the coils is increased and the coils are wrapped (e.g. tightened) closer to the central hub of the stator (i.e. the direction of the coils windings being similar to the direction of the cable windings). Accordingly, when the cable is retracted (being wound over the housing), the number of windings of the coils is reduced and their nominal/average radius increased.

Alternatively or additionally, according to some embodiments of the invention, the coils (or some of them) are configured such that as the housing is rotated with respect to the stator for releasing the cable (reducing the number of windings of the cable), then the number of windings of the coils is decreased and the coils are wrapped (e.g. tightened) closer to the internal perimeter of the housing (i.e. the direction of the coil windings being opposite to the direction of the cable windings). Accordingly, when the cable is retracted (being wound over the housing), the number of windings of the coils is increased and their nominal/average radius is decreased.

As noted above, the use of non insulated coils/spirals improves the packing/wrapping of wires/coils in a given volume of the housing resulting in longer cable when fully extracted. This is because for a given size/diameter of the housing, the length of the retractable cable depends inter alia on the allowable number of rotations of the housing between a fully retracted state of the cable dispensing system and a fully extracted state thereof. In turn, the number of allowable rotations of the housing actually corresponds to the difference between the number of windings of the coils in the fully retracted and fully extracted states. For a given housing and stator dimensions, this difference (and accordingly the number of allowable/possible rotations of the housing) is increased when utilizing thinner spiral/coils elements. Accordingly, the use of non-insulated coils/spirals provides smaller and more efficient design increasing the number of possible rotations of the housing about the stator and thus increasing the length of the cable that can be extracted.

As noted above, use of the non-insulated conductive spirals also allows shortening the electrical path between the bindings of the spirals when they are tightened (when the cable is extracted) thus reducing resistance through the spirals and energy loss. In this connection it should be noted that the configuration of the spiral bindings, which allows them to be in contact with one another when the spirals are wound, is also associated with the smaller size of the cable dispensing system.

According to the present invention, instead of utilizing insulated conductive spirals, the spirals are coaxially and collinearly arranged with respect to the stator (with respect to the rotation axis of the housing) with spaces between them. Specifically, in embodiments configured for medium voltage applications, physical insulation between adjacent conductive spirals is provided (e.g. in the form of insulating disks furnished on the stator and/or on the housing (from its inner side) to provide a physical insulating barrier between the spirals and preventing the creation of arcs even in medium/high voltage ranges. It should be noted that in some embodiments, the retractable cable dispensing system is configured for three-phase operation with voltages of about 400V. In such embodiments the use of such physical insulating barriers (e.g. insulating disks) may be necessary in order to provide proper insulation between the non-insulated conductive spirals while maintaining a relatively small distance between them and thereby reducing the size and form factor of the dispensing system. In cases where such physical insulating barriers are not used, sufficient distance between the spirals should be provided to insure no arcing occurs.

It should be understood that preferably, in some embodiments of the present invention, the retracting/contracting force, which is used to rewind/wind the housing (i.e. to release/wrap the cable wrapped on the housing), is not provided by the conductive spirals themselves but by separate retraction mechanism(s) which may include one or more springs and/or one or more electric-actuators/motors coupled in between the housing and the stator and allowing for actuating relative movement between them. One of the main advantages of utilizing a retraction mechanism that is distinct/separated from the conductive spirals/coils, is associated with the following:

(i) As the conductive spiral is not required to have spring like properties, it may be formed with a stranded wire (e.g. flat braid wire) which is associated with greater flexibility and reduced material fatigue caused by repeated motion and thereby improved reliability.

(ii) Spring-like conducting elements are typically associated with deterioration of their conductance properties during repeated winding and rewinding operations (e.g. due to material fatigue). Thus, avoiding spring-like properties of the spirals may provide improved and more reliable and long lasting conductance through the spirals and reduced energy loss.

(iii) Separation of the conductive spiral from the retraction mechanism facilitates the modular system design described above since the number and the types of conductive spirals may be selected independently and do not affect the retraction force applied to rewind the housing.

It should be noted that according to some embodiments of the invention an over pulling mechanism is provided to prevent rotation of the housing over an allowed degree (e.g. more than a certain number of rotations for which the cable dispensing system is designed). For example such an over pulling mechanism may be configured and/or adjusted to prevent the over pulling of the external cable wrapped on the housing and thereby prevent excess rotation of the housing which may damage the cable dispensing system. Such an over pulling mechanism may be coupled between the housing and the stator, externally or internally to the housing, for preventing over rotation of the housing with respect to the stator. The over pulling mechanism may be implemented by any suitable technique (e.g. utilizing properly constructed mechanical systems which may include gear mechanisms and/or brake/clutch mechanisms).

Specifically, according to some embodiments of the invention, the over pulling mechanism may be implemented by utilizing one or more spirals/coils that are located within the housing. The coils, which serve for over-pulling prevention, may be configured such that their windings are tightened against one another when the housing is rotated over a certain extent to thereby prevent over-rotation of the housing. Specifically, the over pulling prevention coils, may be wound in the same directions as the windings of the cable, or in the opposite direction. Accordingly and respectively, when the cable is extracted/extended, the over pulling prevention coils wound in the direction of the cable would be tightened towards the stator (towards the stator's hub(s)) while coils wound in the opposite direction would be tightened towards the inner perimeter/surface of the housing. The length and number of the coils and the number of windings/bindings in the coils are configured to allow only a certain number of rotations of the housing with respect to the stator before being tightened to the housing inner surface and/or the stator's hub and thereby preventing further rotation of the housing and over pulling of the cable.

In this regard it should be noted that in some embodiments of the invention, the coils serving for conduction of data and/or electricity are used also for over pulling prevention. Alternatively or additionally, one or more dedicated coils/spirals are accommodated within the housing and configured for over-pulling prevention as described above. In the latter configuration, in which dedicated over pulling prevention coils are used, reduced physical stresses are applied to the electric/data terminals by which the electricity/data carrying cables are connected to the housing and/or stator, and thus damage to those terminals is prevented in case of over-pulling of the cable.

Some embodiments are used at charging stations for electrical vehicles. At a charging station, a group of electrical cables may be connected to a vehicle to charge the batteries. Long fixed length cables tend to become tangled and are generally inconvenient. A retractable cable dispensing system reduces cable clutter and entanglement, but may greatly increase electrical resistance. Embodiments described herein provide a cable dispensing system that has reduced electrical resistance.

In some embodiments, a charging station is located at a public location, such as at a service station. In other embodiments, a charging station is located at a private location, such as a garage, or in a semi-private location, such as a business campus. In some embodiments, a charging station may use a retractable cable dispensing system to connect an electrical source to a vehicle, and charge the batteries within the vehicle. In other embodiments, a vehicle exchanges batteries at a battery exchange station, and a retractable cable dispensing system connects a power source directly to the batteries or battery unit.

In accordance with some embodiments, a cable dispensing system is disclosed that comprises a housing assembly that encloses a stator. The housing assembly is rotatable about a central axis through the center of the non-rotating stator. The stator includes a plurality of parallel insulating discs that are axially aligned with the central axis. Each of the insulating discs has a centrally located hub, which may extend outward along the axis from a face of the insulating disc. The insulated discs are all attached to one another in a stacked array. The stator also includes a plurality of parallel coils of flexible non-insulated cable (also referred to in the following as primary coils). Each pair of adjacent coils is separated by one of the insulating discs. Each coil has an inner portion coupled to a hub of an adjacent insulating disc, and an outer portion coupled to the housing assembly. The housing assembly encloses the stator, which includes the insulating discs.

In accordance with some embodiments, a cable dispensing system is disclosed that comprises a housing assembly that encloses a stator. The housing assembly rotates about a central axis. The stator includes a plurality of parallel hubs axially-aligned with the central axis. The hubs are fixedly coupled to each other. Each hub has a first surface and an opposing second surface substantially parallel to the first surface. The stator also includes a plurality of parallel primary coils of flexible cable. Each primary coil has an inner portion coupled to a hub, and an outer portion coupled to the housing assembly. The stator also includes a plurality of parallel secondary coils of flexible insulated data transmission cable. Each secondary coil has an inner portion coupled to a hub, and an outer portion coupled to the housing assembly. The secondary coils are separated from each adjacent primary coil by an insulating disc. The housing assembly encloses the stator, and is rotatably coupled to the hubs.

It is noted that according to some embodiments of the invention, the stator elements including the insulating disks, the central hubs and the primary coils of flexible non-insulated cable, and possibly also the secondary coils are configured as modular elements/structures, which allow the stator to be assembled with any number of parallel primary coils and possibly also with any number of secondary coils where each coil (primary or secondary) may be separated from an adjacent coil by an insulating disk. Specifically each primary coil may be separated by insulating disk(s) from one or two adjacent coil(s) residing from one or both sides thereof.

In some embodiments, the retractable cable dispensing system separates the individual coils with insulating discs, thus allowing medium and/or high voltage through the coils without arcing across the coils. In some embodiments, there are multiple electrical coils, thereby increasing the amount of electrical energy that may be transferred at any one time. In some embodiments, the individual coils are unshielded, which creates a desirable electrical short (shorter electrical path) when the coils are wound or partially wound (i.e., not fully unwound). Because the coils are typically at least partially wound when the cable dispensing system is in use, the unshielded coils reduce the overall resistance through the coils, and thus reduce the amount of energy lost as heat. In some embodiments data control coils are also included, which can modify the flow of electricity through the power cables.

The disclosed embodiments help to remove key impediments to wider adoption of electric vehicles. The embodiments of a retractable cable dispensing system described herein reduce the recharge time by using medium or high voltage connections and data communication channels (e.g. low voltage channels) to optimize recharging. The disclosed embodiments are also cost effective and environmentally friendly by reducing the amount of energy lost as wasted heat. The medium/high voltage and shorter internal electrical path caused by the short between the loops of each coil results in lower electrical energy losses.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the aforementioned embodiments of the invention as well as additional embodiments thereof, reference should be made to the Description of Embodiments below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures.

FIG. 1 provides a perspective view of a retractable cord reel cable dispensing system in accordance with some embodiments.

FIG. 2 provides the same view as FIG. 1, with the top half of the housing assembly removed.

FIG. 3 provides a partially exploded perspective view of a retractable cord reel cable dispensing system shown in FIGS. 1 and 2.

FIG. 4 is a perspective view of the stator shown in FIGS. 1-3.

FIG. 5 is a front view of an end cap of a retractable cord reel cable dispensing system shown in FIGS. 1-4.

FIG. 6 provides a partially exploded view of the stator and end cap of the retractable cord reel cable dispensing system shown in FIGS. 1-5.

FIG. 7 is a perspective view of a coil and an insulating disc of the retractable cord reel cable dispensing system shown in FIGS. 1-6.

FIG. 8 is an alternative perspective view of a coil and an insulating disc of the retractable cord reel cable dispensing system shown in FIGS. 1-7, shown here with the coil separated from the insulating disc.

FIGS. 9 and 10 provide perspective views of a retractable cord reel cable dispensing system in accordance with some embodiments, with portions of the housing assembly cut away to see the electrical terminals.

FIG. 11 provides a perspective view of an exemplary drum system that circumscribes the retractable cord reel cable dispensing system in accordance with some embodiments.

DESCRIPTION OF EMBODIMENTS

Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known components and elements have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

It will also be understood that, although the terms first, second, etc., or primary, secondary, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a primary coil could be termed a secondary coil, and, similarly, a secondary coil could be termed a primary coil, without departing from the scope of the present invention. The primary coil and the secondary coil are both coils, but they are not the same coil.

Embodiments described herein may be used at a private residence, a public charging station, a private commercial facility, or anywhere else that a car may be parked. Some embodiments described herein recharge a battery that is installed in a vehicle. Other embodiments recharge batteries that are not installed in any vehicle, while yet other embodiments are used to charge batteries that are not used to power electric cars. More generally, embodiments of the present invention may be used in rotatable electric devices, such as electric signs or robotic arms, in extension cords, in electric cranes, and other similar locations.

FIGS. 1 and 2 illustrate a retractable cable dispensing system in accordance with some embodiments. The cable dispensing system of the invention includes a stator 140 and a housing structure/assembly 148 which at least partially encloses the stator and is rotatable with respect to the stator. The system also includes two or more electricity conducting mechanisms for carrying electric current/signal between two or more respective electric terminals in the housing 148 and two or more respective electric contacts coupled to the stator 140. According to the invention, the electricity conducting mechanisms include at least one continuous electrically conducting element which provides and maintains continuous electrical contact between the electric contact(s) coupled to the stator and the electric terminal(s) of the housing while enabling relative displacement between them. The continuous electrically conducting element(s) may include the element electrically coupling a ground electric contact of the stator and a ground electric terminal of the housing.

In some embodiments, one or more other of the electricity conducting mechanisms might include non-continuous electrically conducting mechanism(s), e.g. slip rings and brushes, providing electrical contact between the electric contact(s) coupled to the stator and the electric terminal(s) of the housing. While the continuous electrically conducting element provides safe electric contact for the ground part, the discontinuous mechanism(s) may be used for reducing the size (form factor) of the system while providing the rest of the electric/data connections.

As exemplified in the figures, in some embodiments the housing assembly 148 includes an upper housing unit 102 and a lower housing unit 104. In alternative embodiments, the housing assembly 148 includes more or fewer components. In FIG. 2 the upper housing unit 102 is not shown, providing a better view of the stator 140.

Different embodiments of the present invention have different sizes. For example, the housing assembly 148 shown in FIG. 1 may be only a centimeter wide, or could be 25 centimeters wide or larger. In some embodiments the housing assembly 148 generally has a circular cross-section when viewed along the axis 176 formed through the center of the housing assembly. In other embodiments, such as that illustrated in FIG. 1, the housing assembly 148 may deviate from a circular cross-sectional shape. The insulated cable that actually retracts will wrap around the housing assembly in some way. FIG. 11 (described in more detail below) shows an embodiment in which the housing assembly 148 is circumscribed by a drum 188, and the external cable wraps around the drum. It should be noted that the cable is wound around the outer circumference of the housing, and may include multiple electric wires for data/electricity transmission. The electric transmission is carried out via at least three (or five) of such wires (for single- or three-phase arrangement).

In some embodiments the housing assembly 148 is made from an insulating material such as plastic or ceramic. Other insulating materials may also be used for the housing assembly. In some embodiments the housing assembly, or pieces of the housing assembly, are formed by injection molding. In other embodiments the housing assembly may be formed by thermoplastic molding, thermosetting molding, machined CNC, low pressure injection (RIM), or casting of epoxy resin.

FIGS. 1 and 2 illustrate an embodiment in which uninsulated or unshielded cables 106 and shielded data communication cables 108 extend outward from an end cap 112. In some embodiments, the unshielded cables 106 are flat braid cables. In some embodiments, the unshielded cables 106 are circular or oval braid cables. In some embodiments, the unshielded cables 106 are made from a copper or tinned copper material. In other embodiments, the unshielded cables 106 comprise other conductive materials. In some embodiments, the shielded or insulated data communication cables 108 are flat braid cables as illustrated in FIGS. 1 and 2. In other embodiments, the conductive portion of shielded data communication cables 108 has an oval or circular cross section. In some embodiments, the conductive portion of the shielded data communication cables 108 comprises a single piece of material; in other embodiments, the conductive portion comprises a plurality of conductive strands and may be braided or twisted.

The stator 140 includes two or more insulating spacers 114 arranged in a spaced-apart parallel relationship and fixedly attached to one another, while the continuous electrically conducting element(s) is/are formed by at least one coil 116 of a flexible non-insulated cable and is/are separated from an adjacent electrically conducting mechanism by one of the insulating spacers 114. The spacers 114 may be shaped like discs. A rotatable bearing 110 is located between the end cap 112 and the housing assembly 148, allowing the housing assembly 148 to rotate while the end cap 112, discs, and hubs remain stationary (or vice versa). The end cap 112 is described in more detail below with respect to FIG. 5.

In some embodiments, the upper housing unit 102 is attached to the lower housing unit 104 with bolts or screws. FIG. 1 illustrates an embodiment with holes 166 through which bolts may be positioned to secure the upper housing unit 102 to the lower housing unit 104. Cut-outs 164 near the holes 166 provide space for a tool, such as a screwdriver, to manipulate bolts, screws, or the like.

FIG. 2 illustrates a parallel stack of coils 116 and insulating discs 114. As illustrated, each of the coils 116 is separated from an adjacent coil 116 by an insulating disc 114. In some embodiments, the end cap 112 is coupled to the outermost insulating disc 114 on one side of the stack of discs and coils. In some embodiments, end cap 112 is an integral part of an insulating disc that is at an end of the stack. The insulating discs 114 and coils 116 are described in more detail below with respect to FIGS. 7 and 8.

It should be noted, although not specifically illustrated, that the system of the invention preferably includes a mechanism that prevents over pulling of the housing for restricting the number of rotations between the stator and the housing. Such an over pulling prevention mechanism may include one or more spiral-like elements coupled in between the housing and the stator.

FIGS. 1 and 2 illustrate embodiments in which there is a row of electrical terminals 132. In the embodiment of FIG. 2, the terminals 132 are only partially shown because the lower portions of the terminals are inside the lower housing unit 104 (see FIG. 9). In some embodiments, one row of cable openings 160 allow the insulated cables 136 to connect to the electrical terminals 132 (see FIG. 9). In some embodiments the row of electrical terminals 132 secure the outer portions 118 (FIG. 7) of each of the coils 116 to the housing assembly 148. FIG. 9 illustrates this in more detail. In the embodiment of FIG. 2, the cable openings 160 and the electrical terminals 132 are located in the lower housing unit 104. The row of terminals or cable openings could similarly be integrated in the upper housing unit 102. In some embodiments the row of cable openings 160 or the row of electrical terminals 132 are located along an axial length of the lower housing unit 104. In some embodiments, the cables 136 that connect through the cable openings 160 are tightened with screws 182, as shown in FIG. 9. In some embodiments, screws 130 in the electrical terminals 132 hold the outer portions 118 of coils 116 in place. One of skill in the art would recognize that there are many other ways to attach the cables 136 to housing assembly 148, or to electrically connect the outer ends 118 of the coils 116 to respective insulated cables 136. In some embodiments the upper housing unit 102 and the lower housing unit 104 are fabricated from the same mold or the same manufacturing process. In this scenario, openings 158 or other non-functional features may appear on the upper housing unit 102 because of corresponding functionality for the lower housing unit 104 (or vice versa).

As illustrated in FIG. 3, the stator 140 includes: the insulating discs 114, and the end cap 112. In some embodiments, the stator 140 remains stationary while the housing assembly 148 rotates around it. Of the housing assembly 148, insulating discs 114, coils 116, and end cap 112 all share a single longitudinal axis 176 through their centers.

The partially exploded view in FIG. 3 illustrates how the housing assembly 148 encloses the coils 116 and stator 140 in some embodiments. To allow rotation of the housing assembly 148, the inner race of bearing 110 is coupled to the outer circumference of the end cap 112, and the outer race of bearing 110 is coupled to the inner circumference of an upper cut-out 168(1) and a lower cut-out 170(1) of the housing assembly 148. In some embodiments the inner race of the bearing is coupled to the outer circumference of the end cap 112 through a force fit. In other embodiments, the inner race of the bearing is bonded to the outer circumference of the end cap 112 with an adhesive. Similarly, the outer race of bearing 110 may be coupled to the upper cut-out 168(1) and the lower cut-out 170(1) through friction fit (once the upper housing unit 102 and lower housing unit 104 are secured together), adhesive, or other techniques known to those of skill in the art.

Generally, a second bearing 110 is attached to a second end cap or hub from an outermost disc (not shown), which is located on the opposite end of the stator (opposite the end where the end cap 112 is shown in FIG. 3). In some embodiments, the second bearing 110 couples to the housing assembly 148 in a manner similar to that described above for the first bearing 110. A second bearing helps to keep the system balanced.

One of skill in the art would recognize that many different types of bearings made from many different materials could provide the proper interface between the stator 140 and the housing assembly 148, allowing the housing assembly to rotate around the stator. For example, in some embodiments, the bearings 110 are angular contact ball bearings. In some embodiments the balls and races of the bearings are made of ceramic. Some embodiments use spherical roller thrust bearings. Other embodiments use cylindrical roller bearings. In some embodiments high precision bearings are used. In some embodiments a non-metallic material, such as ceramic, is used for the bearings 110 to reduce the risk of electrical shorts or arcing. In some embodiments slide bearings are used. In alternative embodiments, the surfaces between the stator 140 and assembly housing 148 slide without the use of bearings.

In some embodiments, a shaft 174 is located along the axis 176, extending through the middle of stator 140. In some embodiments where a shaft is used, the shaft 174 is fixedly coupled to the insulating discs 114 and the end cap 112. In some embodiments, the shaft is positioned within a passageway formed along the central axis of the stator 140. In particular, FIG. 5 illustrates end cap shaft opening 152, and FIG. 6 illustrates hub shaft opening 154. All of these shaft openings are aligned, and the shaft 174 is positioned within these openings.

FIG. 4 provides a detailed view of the stator 140. In some embodiments, the stator 140 includes the parallel stack of insulating discs 114 and one or more end caps 112 coupled to an outermost insulating disc 114. The coils 116 interspersed between the insulating discs 114 each has an outer portion 118 that extends radially away from the axis 176 (FIG. 3). FIGS. 9 and 10 illustrate in greater detail how the outer portions 118 of each coil 116 are coupled to the housing assembly 148 and electrically coupled to the inner ends 178 of each insulated cable 136.

In some embodiments, the insulating discs 114 are made from a ceramic material, and are sufficiently thick to prevent arcing between adjacent coils. One of skill in the art will recognize that the specific thickness of the insulating discs depends on both the permittivity of the insulating material and the intended voltage and current in the coils separated by the insulating discs. For example, the insulating discs may be 3 or 4 millimeters thick when the voltage across the coils is 400 volts. In some embodiments the insulating discs are circular, but alternative shapes could provide the same functionality as long as the electrical coils are separated from one another.

In some embodiments, the outer circumference of the end cap 112 is circular. Although a circular shape is not required, a circular shape facilitates use of commercially available bearings 110. In some embodiments, the end cap 110 is composed of ceramic or plastic. In other embodiments, alternative rigid insulating materials are used for the end cap 112.

FIG. 5 provides a front view of the end cap 112 shown in FIGS. 1-4. In this embodiment there are eight end cap tunnel segments 126, and two openings 142 for coupling the end cap 112 to the other elements of the stator 140. The tunnel segments 126 in the end cap 112 combine with the tunnel segments 120 in the insulating discs 114 (see FIG. 7) to form tunnels through the stator 140. In some embodiments, one or more bolts or pins are placed through the openings 142 and corresponding openings 156 in the insulating discs (see FIG. 7) to couple the elements of stator 140 together. In some embodiments, each end cap tunnel segment 126 receives a single unshielded cable 106 therein, or a plurality of shielded data transmission cables 108. A plurality of shielded data cables may occupy a single tunnel because the shielding and low voltage nature of the data cables does not cause arcing or shorting. As illustrated in FIGS. 7 and 8, the end cap tunnel segments 126 combine with hub tunnel segments 120 to form tunnels through stator 140. In some embodiments, there are cut-outs 184 extending from each end cap tunnel segment 126 to the outer circumference of the end cap 112. In some embodiments, cut-outs 184 provide space to bend unshielded cables 106 or shielded data communication cables 108.

FIG. 6 provides a partially exploded view of the stator 140. In this view the end cap 112 is shown separated from the nearest insulating disc 114 and coil 116. In some embodiments end cap 112 is integrally formed with the outermost insulating disc 114, and not a separate element, as illustrated in FIG. 6. In this illustration one of the parallel coils 116 and one of the parallel insulating discs 114 is shown separated from the remainder of the stator 140. FIG. 6 further illustrates that all of the coils 116, insulating discs 114, and end cap 112 are axially aligned. In some embodiments, openings 156 in the insulating discs receive pins or bolts as noted above. In other embodiments, openings 156 in the insulating discs hold the lock connector pins 186 of lock connectors 122 (described in more detail with respect to FIGS. 7 and 8). In some embodiments where the openings 156 hold lock connector pins 186, adjacent insulating discs 114 are rotated 180 degrees with respect to each other. In some embodiments, the rotational orientation of an insulating disc may be recognized by the location of the two openings 156 that are next to each other.

FIGS. 7 and 8 illustrate a single coil 116 and an adjacent insulating disc 114 to which the coil is coupled. In some embodiments, the outer portion 118 of each coil 116 is angled, enabling the outer portion 118 to couple to the housing assembly 148, as described in FIG. 1 above and FIG. 9 below. In some embodiments, the central portion of the insulating disc 14 includes a hub 124. FIG. 8 illustrates an embodiment in which the hub extends axially outward from the insulating disc 114, and the coil 116 spirals around hub 124. In other embodiments the hubs 124 are flush with the remainder of the insulating discs 114. In some embodiments, each hub 124 is integrally formed with an insulating disc 114 (e.g., molded integrally), while in other embodiments, each hub is a distinct component that is coupled to the insulating disc 114. In some embodiments each hub 124 includes the central portion of a large insulating disc 114 and a second component that is centrally coupled to the larger disc. Each hub 124 includes multiple hub tunnel segments 120 that extend through the hub 124. The hub tunnel segments 120 are thus visible (when looking at an individual insulating disc 114, as in FIGS. 7 and 8) from either side of an insulating disc 114. The hub tunnel segments 120 are aligned with the hub tunnel segments 120 of adjacent hubs and aligned with the end cap tunnel segments 126 to form tunnels through the middle of the stator 140 that are parallel to the axis 176. In some embodiments the surfaces of each hub 124 are substantially flat, and one or both surfaces of each hub 124 may coincide with the surfaces of the remainder of insulating disc 114.

As shown in FIG. 8, the inner portion 128 of each coil 116 forms the interface between the coil 116 and an unshielded cable 106 (FIGS. 1-3) that is routed through a respective tunnel and out through the end cap 112. In some embodiments the coil 116 and unshielded cable 106 consist of a single contiguous conductive cable. In other embodiments, the coil 116 and the unshielded cable 106 are distinct conductive components that are electrically coupled to one another at the inner end 128 of the coil 116.

In some embodiments the shielded data communication cables 108 are routed through a distinct tunnel in a manner similar to the unshielded cables 106 (see FIGS. 1-4). When data communication cables 108 are routed through tunnels, multiple data communication cables 108 may be routed through the same tunnel. In most embodiments data communication cables 108 do not share tunnels with unshielded cables 106 because the electric field created by the medium/high voltage in unshielded cables 106 could interfere with the data communication. Each data communication cable 108 is similarly connected to, or contiguous with, a coil 116. Because of the low voltage and low current in the data communication cables 108, “shorting” across the spirals or loops in the corresponding coil 116 provides no significant advantage. Thus, the coils 116 attached to data communication cables 108 may be shielded or unshielded. Some embodiments do not utilize shielded communication cables 108.

In some embodiments, the inner end 128 of each coil 116 is mechanically coupled to a hub 124 using a lock connector 122. The lock connector is shaped to prevent the inner end 128 of coil 116 from moving relative to the hub 124. In some embodiments the hub 124 has a hole 144 (FIG. 8) configured to tightly receive the lock connector 122. When the lock connector 122 and the inner end 128 of coil 116 are inserted into the hole 144, it forms a tight mechanical coupling that prevents the inner end 128 from moving relative to the hub 124 as the coil 116 is wound and unwound. In some embodiments, a lock connector 122 has one or two lock connector pins 186 that insert into openings 156 in an insulating disc 114. When a lock connector 122 has two lock connector pins 186, the pins insert into two adjacent insulating discs 114. In some embodiments where the lock connectors have one or two pins 186, the pins 186 hold the lock connectors 122 tightly in place, so the lock connectors 122 need not fit tightly into holes 144. In some embodiments where the lock connectors 122 have two pins 186, the lock connectors 122 prevent adjacent insulating discs 114 from moving relative to each other, and thus provide mechanical stability to the stator 140.

FIG. 8 also helps to illustrate how the electrical path through a coil 116 is shortened when the coil is fully or partially wound (i.e., not fully uncoiled or extended). In FIG. 8 there are multiple individual spirals or loops 150. In an unwound state the spirals or loops 150 do not make contact with one another, so the electrical path is the full length of the unwound coil. As the coil 116 is wound tighter, the spiral rings 150 become closer together, and ultimately may touch each other. Because the coils are unshielded (no insulating sheath), the spirals or loops 150 that touch each other form a “short circuit” radially from one spiral ring 150 to the next. In a wound or partially wound state, the electrical path from the outer portion 118 to the inner portion 128 may be as little as the radius of the outermost spiral ring 150 because each spiral ring 150 shorts to an adjacent spiral ring 150, forming a radial electrical path or partial radial path (not only a spiral electrical path) through the coil 116. In contrast, note that the electrical path through an unwound coil 116 is the unwound length of the entire coil, which is much greater.

In one example, a coil having 12 spiral loops has an innermost spiral loop 150 with a six millimeter radius and an outermost spiral loop 150 with a sixteen millimeter radius. In a wound state the total electrical path may be as little as sixteen millimeters, going from the center to the outer portion 118 along a radial path. But in an unwound state the electrical path would be approximately the sum of twelve circumferences, which is about 83 centimeters. In this example, the electrical path in the wound state is much less than the length of the electrical path in the unwound state. This makes a significant difference in the energy loss from the coil resistance, and reduces the operating temperature of the system. In particular, the resistance is directly proportional to the length of the electrical path, and the loss of energy is directly proportional to the resistance, so any reduction in the length of the electrical path translates directly into decreased energy loss. Experimental tests have shown a reduction of up to 5° C. using unshielded cable for the coils.

FIGS. 9 and 10 illustrate an exemplary structure for coupling the outer portions 118 of the coils 116 to the housing assembly 148. Parts of the housing assembly 148 are cut away in this figure to allow visibility of the other components. FIG. 9 illustrates how the outer portion 118 inserts into terminal 132. In FIG. 10, a portion of electrical terminal 132 is cut away to further show how outer end 118 and insulated cable 136 insert into the electrical terminal 132. Each outer portion 118 is held in place by tightening a screw 130 (shown in FIG. 2) in opening 180. Each terminal 132 also connects to an insulated cable 136, which is inserted through a cable opening 160, and tightened by a screw 182. Each insulated cable 136 is wrapped around the assembly housing 148, either individually or grouped together in a single retracting cable 192 as shown in FIG. 11. Cables 136 are shielded to prevent shorting across adjacent cables. Although only one insulated cable 136 is shown in FIGS. 9 and 10, there is one insulated cable 136 corresponding to each coil 116 in the stator 140. Only a small portion of the insulated cable 136 is depicted in these figures. Each of the outer portions 118 of coils 116 is coupled to a distinct terminal 132 and held in place with a distinct tightening screw 130. FIGS. 9 and 10 thus illustrate the array of terminals 132 along an axial length of housing assembly 148. Those of skill in the art will recognize that there are many alternative structures for coupling the outer portions 118 to terminals 132. In some embodiments, screws 162 hold the terminals 132 in place so that the terminals do not move relative to the housing assembly 148.

The electrical terminals 132 may be held in place by several different means. In some embodiments, insert molding is used, placing the terminals in the intended location prior to injection. In other embodiments, ultrasonic insertion is used. In other embodiments, the space for the electrical terminals in the housing assembly is formed so that there is a tight fit when the electrical terminals are inserted. In other embodiments, the terminals 132 have a loose fit until the upper and lower housing units 102 and 104 are stuck together (at which point there is a tight fit). In some embodiments, screws (e.g., screws 162) or bolts are used to hold the electrical terminals 132 in place, and these screws or bolts may be hidden when the unit is fully assembled.

FIGS. 1-10 illustrate the internal structure of an exemplary cable dispensing system. These figures do not illustrate the retractable cables that are attached to the housing assembly 148. FIG. 11 shows an exemplary embodiment of a drum system that connects the housing assembly to an external cable that retracts. Two or more shielded cables 136 connect to the electrical terminals of the housing assembly 148. In the embodiment shown in FIG. 11, the shielded cables 136 are further encased in a retracting cable 192. Although the shielded cables 136 need not be further encased in a retracting cable 192, the use of a single retracting cable 192 helps to prevent individual shielded cables 136 from becoming tangled, bent, or otherwise damaged. The use of a single retracting cable 192 is particularly useful when there are many shielded cables 136.

The retracting cable 192 wraps around a drum 188, which may be substantially circular, as shown in the embodiment of FIG. 11. In some embodiments, there is a stop block 194 connected to the retracting cable 192. When used, the stop block 194 prevents the retracting cable 192 from retracting too far. In particular, the stop block 194 would not be able to pass through the rollers 190. One of skill in the art would recognize that there are many alternative means to prevent the retracting cable 192 from retracting too far. In addition to working with a stop block 194, rollers 190 enable smooth operation of the cable dispensing system.

The outer end 146 of the retracting cable 192 would typically connect to a plug, socket or other mechanism suitable for connecting to an external device (not shown in FIG. 11).

In some embodiments, one or more of the coils 116 are made of spring metal, which rewinds the retracting cable 192 around the housing assembly 148 after use. In other embodiments, the retracting cable 192 is rewound about the housing assembly 148 by a motor, which may be located outside of the housing unit. In some embodiments there is an external mechanical spring system connected to the housing unit 148 to rewind the retracting cable 192. As noted above, use of a separate retracting mechanism (i.e. distinct from the conductive coils/spirals e.g. motor and/or spring located outside the housing) is advantageous for several reasons, and at least because it prevents/reduces deterioration in the conductivity of the conductive coils. It also allows use of stranded conductors for the spirals, thereby improving their mechanical stability, and facilitating an improved electric contact between their bindings when the latter are tightened (improving conductivity of the coils), and facilitating modular design of the cable dispensing system in which the number of coils does not affect the retraction force applied to the housing.

Once assembled in position, such as in a charge station or in an electrical vehicle, one end of the power cables connects to a power source and the other end connects to a load, such as a battery to be recharged. There are at least two unshielded cables 106, but in some embodiments there may be many more unshielded cables 106. The embodiment in FIGS. 1 and 2 has seven unshielded cables. Some embodiments have only unshielded cables 106, whereas other embodiments have two or more data communication cables 108 in addition to the unshielded cables 106.

It should also be understood (although not specifically illustrated in the figure) that in some embodiments of the invention certain one or more electrical connections and/or data/signal connection, between the stator and the housing may be provided by utilizing conventional techniques (e.g. rings and touch brushes) while at least one electrical connection (e.g. grounding/earthing connection) is provided by a conductive spiral/coil in the manner described above. The latter may be used for providing continuous and reliable electrical contact of grounding between the ground wire in the electric cable wrapped around the housing and an earthing connection/terminal of the stator.

The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. 

1. A cable dispensing system, comprising: a stator; a housing at least partially enclosing the stator and configured to rotate relative thereto; and at least two electricity conducting mechanisms configured for carrying electric current between at least two respective electric terminals in the housing and at least two respective electric contacts coupled to the stator; said at least two electricity conducting mechanisms including at least one continuous electrically conducting element configured for providing and maintaining continuous electrical contact between at least one of said at least two electric contacts coupled to the stator and at least one of said at least two electric terminals of the housing while enabling relative displacement between them.
 2. The cable dispensing system of claim 1, wherein said at least two electricity conducting mechanisms include at least one non-continuous electrically conducting mechanism configured for providing electrical contact between at least one of said at least two electric contacts coupled to the stator and at least one of said at least two electric terminals of the housing while enabling relative displacement between them.
 3. The cable dispensing system of claim 1, wherein said at least one continuous electrically conducting element comprises the electrically conducting element adapted for providing electric coupling between a ground electric contact coupled to the stator and a ground electric terminal of the housing.
 4. The cable dispensing system of claim 1, wherein said stator comprises at least two parallel insulating spacers fixedly attached to one another; and said at least one continuous electrically conducting element is formed by at least one coil of a flexible non-insulated cable and is separated from an adjacent electrically conducting mechanism by one of the insulating spacers.
 5. The cable dispensing system of claim 4, wherein the spacer has a disc-like shape.
 6. The cable dispensing system of claim 4, wherein at least some of the insulating spacers include a centrally located hub and said at least one coil has an inner portion coupled to a hub of a respective one of the insulating spacers, and an outer end fixedly coupled to the housing.
 7. The cable dispensing system of claim 6, wherein each hub comprises one or more tunnel segments that extend along a rotational axis of said housing with respect to the stator; and the tunnel segments of one or more of the adjacent hubs are aligned to form tunnels through the insulating spacers.
 8. The cable dispensing system of claim 7 wherein a non-insulated cable of said at least one coil is routed through a respective one of the tunnels.
 9. The cable dispensing system of claim 7, further comprising at least one axial cable extending through a respective one of the tunnels and electrically connected to an inner portion of said at least one coil.
 10. The cable dispensing system of claim 4, further comprising at least one electrical terminal disposed along an axial length of the housing, where said at least one coil is connected to a respective one of the terminals.
 11. The cable dispensing system of claim 1, further comprising an insulated cable comprising multiple electric wires that are electrically coupled to a respective one of the electrically conducting mechanisms and wherein said insulated cable is wound around the outer circumference of the housing.
 12. The cable dispensing system of claim 11, wherein the insulated cable comprises at least three electric wires.
 13. The cable dispensing system of claim 4, wherein said at least one coil comprises an inner end coupled to an outer end via multiple spiral coils, where in an at least partially wound state, an electrical path is formed between the inner end and the outer end of said at least one coil along an at least partially radial path between the inner end and the outer end.
 14. The cable dispensing system of claim 1, further comprising at least one coil of one or more insulated data cables separated from an adjacent electricity conducting mechanism by an insulating spacer, where the at least one coil of one or more insulated data cables is disposed within the housing.
 15. The cable dispensing system of claim 4, further comprising a biasing mechanism for rotating the housing to rewind any dispensed cable.
 16. The cable dispensing system of claim 15 wherein said biasing mechanism includes at least one of a spring or an electric motor.
 17. The cable dispensing system of claim 1 further comprising an over pulling prevention mechanism coupled in between said stator and said housing and adapted for restricting the number of rotations between said stator and said housing.
 18. The cable dispensing system of claim 16 wherein said over pulling mechanism comprising at least one spiral like element coupled in between said housing and said stator.
 19. The cable dispensing system of claim 1, wherein said stator comprises a plurality of parallel insulating spacers attached to one another; and a plurality of continuous electrically conducting elements including a plurality of parallel coils of a flexible non-insulated cable, wherein each of said coils is separated from an adjacent electrically conducting mechanism by one of the insulating spacers. 